First of all, I want to thank you mmmbot for answering.

Sorry if I didn't write it well. By writing exp I meant e to the power.

So I mean: [e to the power of (1 + (O(1/n))^2)] = e + O(1/n)


P.S.1: Could you tell me how to write it in the post so as it will appear correctly?
P.S.2: What you say is right: exp(1) and e are the same thing. That is what I mean.